The objective of this Core is to provide phantoms of consistent quality to all projects in this program. The phantom development proposed in this core is aimed at developing a set of contrast-detail (CD) phantoms applicable to both sonographic and elastographic imaging. Standard methods and materials will be used in phantom construction. Ideally these phantoms will be thermally and temporally stable, and applicable to CD analysis in both sonography and elastography. Several options for combinations of materials for these phantoms are proposed. Construction of test samples is necessary to determine the best set of materials and the longevity and uniformity of the resulting phantoms. Following construction and measuring properties of test samples the best combination of materials will be determined, and CD phantoms will be constructed.